Continue to provide the service function of performing assays for CEA on serum samples collected by Mayo Clinic and stored at the NCI Serum Bank for research projects associated with the Division of Cancer Biology and Diagnosis. The data from these tests will be provided regularly to the Serum Bank and also to NCI on request as long as funds are available to support a technician, supplies, and services. This testing allows comparison of the discriminatory ability of new diagnostic assays with that afforded by the CEA assay. Since the Serum Bank and all of the specimens are at the Mayo Clinic this arrangement for on site testing for CEA greatly simplifies the logistics for such evaluations.